From: James Clark Date: Tue, 25 Mar 2025 11:58:47 +0000 (+0000) Subject: coresight: Only check bottom two claim bits X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a4e65842e1142aa18ef36113fbd81d614eaefe5a;p=users%2Fdwmw2%2Flinux.git coresight: Only check bottom two claim bits The use of the whole register and == could break the claim mechanism if any of the other bits are used in the future. The referenced doc "PSCI - ARM DEN 0022D" also says to only read and clear the bottom two bits. Use FIELD_GET() to extract only the relevant part. Reviewed-by: Leo Yan Reviewed-by: Yeoreum Yun Signed-off-by: James Clark Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20250325-james-coresight-claim-tags-v4-2-dfbd3822b2e5@linaro.org --- diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index 17f931f7e6165..9f183064285da 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -131,7 +131,8 @@ coresight_find_out_connection(struct coresight_device *csdev, static inline u32 coresight_read_claim_tags_unlocked(struct coresight_device *csdev) { - return csdev_access_relaxed_read32(&csdev->access, CORESIGHT_CLAIMCLR); + return FIELD_GET(CORESIGHT_CLAIM_MASK, + csdev_access_relaxed_read32(&csdev->access, CORESIGHT_CLAIMCLR)); } static inline bool coresight_is_claimed_self_hosted(struct coresight_device *csdev) diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index 82644aff8d2b7..38bb4e8b50ef6 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -35,6 +35,7 @@ extern const struct device_type coresight_dev_type[]; * Coresight device CLAIM protocol. * See PSCI - ARM DEN 0022D, Section: 6.8.1 Debug and Trace save and restore. */ +#define CORESIGHT_CLAIM_MASK GENMASK(1, 0) #define CORESIGHT_CLAIM_SELF_HOSTED BIT(1) #define TIMEOUT_US 100